Safety lock



June 1 9, 1945. A. A. J. COHAN SAFETY LOCK F1191; Jan. 11, 1945 Patented June 19, 1945 Albert A. J. Cohan, Philadelphia, Pa.

Application January 11, 1945, Serial No. 572,337.

4 Claims. (Cl. 292--346) This invention relates to safety locks and pertains more particularly to improvements in nontamperable night latches for doors.

The principal purpose of the invention is" to i provide a night latch with simple, durable and automaticallyoperable safety devices whicheffectively guard the main bolt of the latch from being pried open or cut off by a tool inserted in the crack between the closed door and the jamb, and i which also afford auxiliary locking means and A recommended embodiment of the invention is shown in the accompanying drawing, but it will be understood that the structural details of the mechanism herein illustrated and described may be varied to suit particular conditions or installa- Fig. 4 is an end view of the outer face of the lock proper; and i Fig. is a section on line 55 of Fig. 3, with the face plate of the strike partly broken away.

The improved safety lock comprises the lock proper in which is screwed on the inside of the door H and which may be of the ordinary night latch type having a spring-pressed bolt l2 movable to inoperative position by a knob l3 and held either open or closed by the usual thumb catch l4; and keeper or strike l5 having a 'face plate l6, screwed to the jamb I1, and adapted to receive the beveled face 18 of the bolt [2, as indicated by thebroken lines of Fig. 2. These parts may be of any desired size, shape or construction and the internal mechanism of the lock proper is immaterial to the present invention which is concerned with a safety plate l9 incorporated in the strike and actuated by lugs or jaws 20 on the face of the lock l0.

The safety plate I9 is a relatively wide piece of stout metal, slidable across the. bottom 2| of the strike and guided in notches 22 (Fig. 3) of the face It. It is normally retracted within the strike by a pair of coiled springs 23 suitably atthus increase the security of the improved lock.

are'retained by a bar loops.

The plate [9 has a pair of upstanding cam members 25 spaced apart so that the bolt end [8 maybe received therebetween, and also spaced from the forward edge of the safety plate so that 24 passed through theirend the latter may be received in aslot 26 in the face 21 of the lock l0 when the lock is secured (Fig. 2). The rearward edges of the cams 25 are inclined atan angle of approximately 45 degrees, and the rearward or inner edges of the lock lugs are'similarly inclined to cooperate therewith. Said lugs are spaced a distance equivalent to the lateral spacing of the cams, so that the inclined surfaces of the cooperating elements are engaged with a. sliding action when the door is closed, thereby automatically projecting the safety plat 19 to locking position as shown in Fig. 2.

The top of the strike has a pair of slots 28 through which therespective lugs 20 pass when the door is closed, and a central tongue 29 depending from the top of the strike at the front thereof engages the top of the end l8 ofthe main tached to the back of the strike. As here shown I bolt l2 when the latter is closed, to prevent the opening of the door until the bolt is withdrawn.

The closed bolt is thus protected against tampering by the automatically closed safety plate which bridges the crack 30 between the door and jamb exteriorly of the bolt and thus prevents the forcing of the bolt by an implement inserted in the crack and pressed against the beveled face of the bolt, and also by the interengaged cam and lug members which further impede any attempt to saw through the safety plate and the bolt. The safety plate also serves as an auxiliary bolt,

but that plate is automatically withdrawn by the retracting springs 23 when the door is opened to release the lugs 26 from engagement with the cams 25, after the main bolt is retracted.

I claim:

1. In a night latch of the character described having a lock attachable to a door, a strike attachable to a jamb and a bolt movable from the lock into the strike, safety devices comprising a lug projecting from the face of the lock and adapted to enter the strike, a plate disposed within the strike and movable relatively thereto to engage the face of the lock,.said plate having a cam engaged by said lug when the door is closed thereby automatically to project the plate from the strike toward the lock, and resilientmeans normally retracting said plate. t 2. In a night latch of the character described having a lock attachable to a door, a strike attachable to a jamb and a bolt movable from the look into the strike, safety devices comprising a. lug projecting from the face of the lock and adapted to enter the strike, a plate disposed within the strike and movable relatively thereto to engage the face of the lock, the face of the lock having a slot receiving the end of the projected plate, said plate having a cam engaged by said lug when the door is closed thereby automatically to project the plate from the strike into the lock, and resilient means normally retracting said plate. I

3. In a night latch of the character described having a lock attachable to a door, a strike attachable to a jamb and a bolt movable from the lock into the strike, safety devices comprising a pair of spaced lugs projecting from the face of through which the lugs enter the strike, a plate the lock on opposite sides of its bolt, the front of the strike having complemental notches is closed thereby automatically to project the plate from the strike and into engagement with the face of the lock, and spring means normally tachable to a jamb and a bolt movable from the look into the strike, safety devices comprising a pair of spaced lugs projecting from the face of the lock on opposite sides of its bolt, the front of the strike having complemental notches through which the lugs enter the strike, a plate slideable within the strike toward and from the face of the lock, the face of the lock having a slot receiving the end of the projected plate, said plate having a pair of spaced cams engaged by said lugs when the door is closed thereby automatically to project the plate from the strike and into said slot, and spring means normally reslideable-within the strike toward and from the 20 tracting said plate into the strike.

face of the lock, said plate having a pair of spaced cams engaged by said lugs when the door ALBERT A. J. COHAN; 

